Japanese Laid-Open Patent Publication No. 2007-181010 discusses a path protection method. According to the path protection method, in a section connected in a point-to-point manner in a virtual network, a virtual network identifier assigned to one or more users is associated with one management virtual network identifier, is identified as one path, and a working path and a standby path are set with the use of paths each of which is identified as one path as mentioned above. When switching is performed between the working path and the standby path, service class information included in the management virtual network identifier is used in a manner such that a path having a management virtual network identifier having higher service class undergoes the switching with priority given.